Trane Voyager

[toxic11]

Just recently I have worked on a bunch trane little 5 ton voyagers. I came accross a weird issue. When you turn the disconnect off and then turn it back on, the supply fan bangs on right away. U sually there is like a 15 seconds delay before if comes on. These fan run all the time and they stage heat and cooling as they need it. So I have checked the TCO2 sensro (high limiut cutout) which usually makes the fan come on right away. But it was good. And If it was bad the heat wouldnt come on. And the weird thing is that the unit works totally fine. I just cant figure out why is it doing that.
Did anyone came accross this issue too.

[jackintheboxtec]

Fan delay relay..Probably bad or bypassed

[toxic11]

Is that relay built in to the UCP board.

[Phisher]

Have you checked the fan contactor to make sure the contacts aren't welded shut.

[supertek65]

time delay / stuck contactor

[Chris_Worthington]

Just recently I have worked on a bunch trane little 5 ton voyagers. I came accross a weird issue. When you turn the disconnect off and then turn it back on, the supply fan bangs on right away. U sually there is like a 15 seconds delay before if comes on. These fan run all the time and they stage heat and cooling as they need it. So I have checked the TCO2 sensro (high limiut cutout) which usually makes the fan come on right away. But it was good. And If it was bad the heat wouldnt come on. And the weird thing is that the unit works totally fine. I just cant figure out why is it doing that.
Did anyone came accross this issue too.

Had one here as well and ended up contributing it to a ground issue and ripped out the board all together.

This RTU had been previously modified for cooling 365 with fan cycling controls, defrost stats, etc. due to no possible way of installing an economizer.

The board in our case served little value at that point, it merely served as a gateway for the heating and blower commands.

The problem with the fan running all the time in our case was during the times where nothing but the blower was running, was the air being dumped directly on the occupants below. They considered it cold. (Bad duct/everything else design)

Not necessarily the right fix, but it was what it was....

Interesting question though as we have god knows how many of the same out there and have only seen this once.

[mallron]

Do you see this on all the units? Is there a control system in place? The fans might be set to continuous.

[badbillr]

are you talking about when the power is re-applied to the unit, the blower bumps on for a brief second and then right back off? If so, when the power is applied an electrical field is created, the pcb board reacts to the power in-rush by collapsing the field. When the field collapses, a voltage spike/surge is created, providing voltage to the blower motor & relay for a split second.

[toxic11]

like I said, these fans are set to run all the time and bring heating or cooling at anytime is needed. the contacts are not welded. The unit works perfectly fine. there is about 30 of these units out there. And only this one when ever I turn the power off and then turn it back on I notice that there is no delay on the supply fan like in any other units. This one just bangs on right away.